I like what Ed Walsh has to say about this:
In an earlier post, I mentioned the trouble comedians were having coming up with a funny trope to use to poke fun at President Obama. The experts’ conclusion seems to be that Vice President Biden is the fattest target for humor in the Administration.Now we see the story developing further. It’s not just Biden, see, but Obama’s reaction to Biden that is becoming a reliable comic routine. In this scenario, Barack Obama is Joe Biden’s straight man.It’s promising. As this Politico clip of segments from “The Daily Show” and “The Tonight Show” makes clear, watching the habitually on-message president react to Biden’s howitzer-in-a-hurricane rhetorical style is pretty funny. And it offers the hint of a crack in Obama’s cool public face.